The Efficacy of Phonological Processing Treatment on Stuttering Severity in Persian Pre-School Children.

Objectives
Correct phonological encoding is crucial to fluent speech production. Phonological working memory and phonological awareness are important phonological processes that affect phonological encoding. The purpose of this study was to investigate the effect of phonological processing on stuttering severity of Persian pre-school children.


Materials & Methods
Six children were targeted in this study in Ahvaz City, southern Iran in 2018, with Quasi-experimental design (Before and after clinical trial). These children participated in a treatment protocol, scheduled in 13-sessions. The treatment protocol of the phonological processing included nonword repetition in the phonological working memory and phonological awareness therapy. Overall, 30 nonwords were taken to examine the phonological working memory. The Persian test of language development was taken to examine phonological awareness. Stuttering severity measurements were performed with pre- and post-treatment. The severity rating was instructed to the parents based on Guitar protocol. They were asked to keep score every day until the end of the treatment sessions, and they reported the score to the therapist.


Results
The stuttering severity score in pre and post-treatment was significant (P=0.027), and in the follow-up, phase was not significant (P=0.236); stuttering severity was reduced in children who stutter. Moreover, the severity rating score reported by parents during treatment was significant (P= 0.0001). This showed a reduction in stuttering severity.


Conclusion
The poor performance of phonological awareness and phonological working memory in phonological processing affect stuttering severity. Treatment of sub-systems of phonological processing can have an important role in reducing stuttering severity and increasing speech fluency.


Introduction
Stuttering is generally known as a multi-factor phenomenon (1). Given the complexity of stuttering, many assumptions have been proposed regarding its origins (2). One of the most comprehensive psycholinguistic theories on the cause of stuttering is the Covert Repair Hypothesis (3). Based on the Levelt model, this hypothesis suggests the process of word production and seeks to investigate the causes of stuttering, including repetition of sound, prolongation, and blocking during the fluent speech (4). According to the Levelt model and covert repair hypothesis, before phonic production, correct phonological encoding is important for fluent speech production (5)(6)(7)(8)(9).
Phonological processing, as an umbrella term, includes various skills, which have many effects on phonological encoding (10). Phonological working memory and phonological awareness, which are part of phonological processing, are factors affecting phonological encoding (1,8,11). Working memory is a neuro-cognitive system that includes the central executive, a phonological loop, a visuospatial sketchpad, and an episodic buffer (2,9,12,13). Phonological loop plays an important role in phoneme encoding and correct phoneme retrieval in the working memory (1,5). Another factor in phonological processing is having phonological awareness skills (8). Phonological awareness skills refer to an individual's ability to analyze, recognize, discriminate, and manipulate phonemes in speech, not considering the word size and meaning (8).
Studies have focused on the factors influencing phonological encoding and, by examining the results; phonological processing can be affected by various language and speech disorders, which cause phonological encoding disorders (14)(15)(16). One of the speech disorders is stuttering (5,8,12,13,17).
Phonological awareness studies were conducted on children who stutter (CWS). Phonological encoding ability in CWS was examined. There are differences in phonological awareness ability of the two groups of children who do and do not stutter (8). Studies in the field of phonological working memory have investigated the phonological loop, which is part of the active phoneme memory, in people who stutter (PWS). These studies used a nonword repetition task to examine this part of the working memory. Phonological working memory performance in PWS showed weaker than people who do not stutter (PWNS) (1,2,12,(18)(19)(20).
The present study was conducted to investigate the effect of phonological processing treatment on the reduction of stuttering severity of pre-school children. The aim of this study was to evaluate and cure the non-verbal dimensions in order to enhance speech fluency of children who stutter.

Materials & Methods
This study with Quasi-experimental design (Before and after clinical trial) targeted six children who stutter (3 girls and 3 boys) with an average age of 6 yr and 4 months.  10 were included in the study because they were considered weak in this ability (5). Persian test of language development showed validity over 0.9 (22). This auditory discrimination subtest was calculated with the differentiation power of 0.80 in the Persian language development test (22).
Phonetic test was calculated with a correlation span test was calculated by methods of split-half and testretest 0.71 (24). The reliability of Stuttering Severity Instrument was calculated through two methods of inter and intrajudge higher than 0.90 (26).
Before starting intervention sessions, one week was allocated to evaluate the CWSs. One week before starting treatment, the Persian version of SSI4 was performed for 3 sessions in order to determine the children's stuttering severity. In order to assess the level of phonological awareness of the children, a standardized phonological awareness test was used (21). Prior to the treatment, the severity rating was trained to the parents based on the Guitar protocol, and the agreement of parents and the speechlanguage pathologist on the severity of stuttering was investigated. The parents were asked to take a score every day until the end of the stuttering sessions, and report the score to the therapist, with a score of zero (no stuttering) to 10 (highest stuttering) (27).
Subjects were treated with 13 sessions of 45 min.
The intervention was performed in two parts in each session. The subjects were first instructed that a number of meaningless words would be expressed to them, and they should carefully listen to the meaningless words and repeat them immediately after the meaningless word was uttered. In order to ensure that the subject fully understood the steps involved in doing therapy tasks, 5 nonwords were stated as training items. After the training phase, nonword packets were expressed by the therapist and the subject repeated each nonword after hearing it.
During each session, each packet was repeated 5 times, and the subject was given the opportunity to hear each nonword 5 times and try to repeat it more accurately. In each session, a new nonword packet was provided to the subject and in the event of failure in that package, an equivalent packet was presented for the next session (28,29).

Treatment of phonological awareness
The second part of the treatment sessions included phonological awareness therapy.
Seven phonological awareness subtests were  From the first to the third session, repeat 2 packages of nonwords, and from the fourth session onward repeat one package of nonwords until the end of each session Treatment 14 educational packages from each sub-test two educational packages: In the first session, two packages of the first sub-test were used, while in the next 12 sessions, a therapeutic package of 6 remaining subtests were utilized.

Posttreatment
Post-test Nonword repetition task, the Persian version of SSI4, Phonological awareness test Follow-up One week after the treatment

Results
The summary of the subjects' biography is presented in Table 2   The Wilcoxcon test was used for statistical analysis of stuttering severity pre-and post-intervention. Table 3 shows the data before and after the treatment.
The results of statistical analysis (P<0.05) showed a significant difference. Table 3 shows

Participant 4:
The average stuttering severity before the treatment was reduced from 25 to 22 after the treatment. In all subtests, recovery was observed and the score was increased. In the phonological awareness section, the most significant change was observed in the identification of the words with the same initial phoneme. Severity rating scores by the parents were reduced from 5 to 3.

Participant 5:
The average stuttering severity before the treatment was reduced from 20 to 18 after the treatment. In all the subtests, recovery was observed and the score increased. In the phonological awareness section, the most significant change was observed in the identification of the words with the same initial phoneme. Severity rating scores by the parents were reduced from 5 to 3.

Participant 6:
The mild stuttering severity before the treatment was reduced from score 16 to score 11 after the treatment. In all the sub-tests, recovery was observed and the score increased. Like other participants, in the phonological awareness section, the most significant change was observed in the identification of the words with the same initial phoneme. Severity rating scores by the parents were reduced from 5 to 3. Friedman test (repeated measures) was used to analyze the severity rating provided by the parents.

Severity rating
The result of the severity rating score of the subjects (P=0.0001) is significant.

Follow-up
In order to evaluate the effect of treatment on stuttering severity of CWS, severity rating was recorded each day by the parents one week after treatment. Statistical analysis in the follow-up phase was done using the Friedman test, and the results were not significant (P=0.236). Therefore, no difference in treatment period and treatment stability was observed.

Discussion
The aim of this study was to investigate the effect of phonological processing treatment on stuttering severity of Persian pre-school children and to assess

Follow-up
In order to evaluate the effect of treatment on stuttering severity of CWS, severity rating was recorded each day by the parents one week after treatment. Statistical analysis in the follow-up follow up, P*: Participant Figure 1. Changes in the rate of stuttering severity by parents in treatment and follow-up sessions their pre-and post-treatment scores. In general, the outcomes of this study include the scores obtained in phonological working memory, phonological awareness, and stuttering severity.
In short, the process of nonword production occurs in the phonological loop without the need for prior vocabulary knowledge. As selecting target phonemes from other phonemes during the production of a word in the phonological loop of PWSs takes time, the probability of an error in selecting a correct phoneme is increased (4,5). In this study, phonological working memory in CWS was treated using a nonword repetition Finally, dysfluency reduction in these children was reported. In addition to focusing on the nonword repetition task to improve phonological working memory, the study used a motivational plan to enhance participants' learning. Therefore, as mental and psychological factors have a very significant effect on the function of CWS, the reduction in the stuttering severity observed in the participants in the study was completely due to the improvement of phonological working memory (28).
In the phonological awareness part, this study aspects of phonological encoding of linguistic programming (8). By comparing phonological awareness in CWS and CWNS, another study reported stuttering as an effective factor in reducing the score in the phonological awareness test (30).
Outcome measurement of this study, in addition to confirming the weakness in phonological awareness of CWS, showed a post-treatment decrease in stuttering severity of the subjects.
Therefore, this part of phonological processing, along with the treatment of phonological working memory, can be effective in reducing stuttering severity. Contrary to the results of this study on reduction of stuttering severity, in another study, with a weakness in the phonological awareness of CWS compared to CWNS, there was no significant relationship between phonological awareness and dysfunction in these children, which could be due to small sample size. However, special attention should be paid to the potentials of phonological awareness in evaluating and treating CWS (19).
The important aspect of this study was the comparison of the stuttering severity of CWS pre-and post-phonological treatment. Stuttering severity in SSI4 ranges from very mild to very severe, and each type of stuttering severity has a specific numerical range. By comparing the mean stuttering severity score before and after the intervention, a decrease in the mean stuttering severity score was observed in all subjects.
Moreover, by doing statistical analysis on the severity rating by parents, the stuttering severity score in all subjects decreased.
Stable changes in stuttering severity were observed by comparing the average severity rating determined by the parent during the treatment and the weekly follow-up of the sustained effect of the treatment. However, given that the followup period of children was considered one week after the treatment, the score could be considered as a suitable measure for the assessment of the therapeutic sustainability. This treatment was performed as an experimental and indirect treatment of the stuttering severity of CWS. Therefore, a shorter follow-up period was considered to allow parents to go to treatment centers more quickly to continue the stuttering treatment. This research will help to plan the future treatment interferences in the treatment of PWS. It will also be important to focus on these two areas in order to expedite the treatment of children and prevent language problems that they will be encounter during school times. All authors agreed to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.